Composite indirectly illuminated instrument panels



Feb. 4, 1958 R. E. PARTRIDGE 2,821,799

COMPOSITE INDTRECTLY ILLUMINATED INSTRUMENT PANELS Filed Aug. 16, 1954 2 Sheets-Sheet 1 IN VEN TOR. RA J MO/VD 5 PAP/700M Feb. 4, 1958 Q R. E FARTRIDGE 2,821,799

COMPOSITE INDTREC'Z'LY ILLUMINATED INSTRUMENT PANELS Filed Aug. 16, 1954 2 Sheets-Sheet 2 INVEN TOR. PA VMO/VD E. PAPfE/DGE United States Patent COMPOSITE INDIRECTLY ILLUMINATED INSTRUMENT PANELS Raymond E. Partridge, Seattle, Wash. Application August 16, 1954, Serial No. 450,065 '1 claim. or. 40-130 The present invention relates to instrument panels for use in vehicles such as aircraft and is particularly concerned with such panels which are indirectly illuminated. It has been proposed heretofore to provide instrument panels which at night would be illuminated and which would bearlindicia capable of being read easily in daylight. It" is important that such an instrument panel at night have well illuminated indicia without producing anyappreciable glow or reflection.

Various proposals have been made in the past for providing instrument panels of the character mentioned, but these have been expensive to make and in some cases have been difiicult to keep clean or unsatisfactory for some other reason.-

A principal object of the present invention is to provide an illuminated instrument panel which can be produced relatively quickly and economically, yet which will have asgood or better performance than any prior illuminated instrument panel.

- It is a particular object to reduce the cost and increase the accuracy of producing such illuminated instrument panels by reducing the cost of applying the indicia to the panel structure. Another object is to enable such indicia to be reproduced economically on a large number of instrument panels if desired. i

A furtherobject is, to protect completely the indicia from abrasive wear and deterioration of other types. It is also an object to enable instrument panels of var: ious'types' tobe made with substantially equal facility. In general"the foregoingobjects can be accomplished byutilizing a composite panel structure including a central, relatively thin, indicia-bearing layer, a back, relativ ely thick, light-transmitting layer, and a front protective layer which may be made of any desired thickness. of these layers may be formed of a separate sheet of sttick, and,then, after the indicia has been applied to the central Iayerfthe, three sheets will be intimately bonded together over their entire surfaces to form a unitary composite panel I The ifidiciais applied to the central sheet by a printing or photographic process, and the portion of the sheet otherthan the indicia is rendered opaqu e,'while the indieia portion is at least highly translucent and may be transparent, atleast in part. t A

As illustrative of types of panels embodying the featurespf ,the present invention, representative panel structnresare shown in the accompanying drawings. Figure 1 is aftop perspective exploded view of the sheets utiliied in the fabrication of one type of panel made in accordance with the present invention, parts being'broken away. Figure 2 is a top perspective view of a portion of. the eor'npleted panel, showing the sheets of Figure 1 bonded intoaunitary',structure.j I

Figure} is a top perspective viewof the center sheet of panelshown in Figures Land 2,=parts being broken awa but viewe d gfrornfthe side ;opposite that. seen in ice Figure 4 is a top perspective view of sheets from which an alternative form of panel embodying the principles of the present invention may be constructed, shown in exploded relationship and having parts broken away, and Figure 5 is a top perspective view of a portion of a panel formed of sheets such as shown in Figure 4 bonded together.

Figure 6 is a top perspective view of the central sheet shown in Figure 4, but seen from the opposite side, parts being broken away.

As shown best in Figure 2, the completed panel is composed of three sheets, 1, 2, and 3, which are bonded intimately together. Sheet 1 is the face panel or front panel which covers and protects the indicia-bearing panel 2. Panel 1 should be made of reasonably hard, transparent plastic material such as clear vinyl or acetate plastc sheet. Preferably the outer face of this sheet is treated so that it will not have a shiny surface, but rather will have a fiat or non-reflecting surface. Thus the face of this sheet which is exposed can be sprayed with a. vinyl plastic spray. This sheet must be thick enough to protect the intermediate orindicia-bearing sheet 2 from being scratched, but otherwise its thickness may vary depending upon the total thickness of the panel desired. Its thickness may vary from .005 of an inch to .025 of an inch for example. The thinner the sheet, the less will be the distortion of the indicia when the panel is viewed from an angle.

, .The central or intermediate panel which bears the indicia preferably is thinner than the base sheet 1, and may, for example, be-from .003 of an inch to .010 of an inch. Like the outer surface sheet 1, the intermediate sheet 2 maybe of vinyl plastic, acetate plastic, or other equivalent plastic material. Preferably this sheet is of translucent. rather than transparent material of some selected color. Ordinarily the color selected should be that which it is desired for the indicia to be when the panel is not illuminated. A preferred color, therefore, is white, although it might be gray, red, or some other light color.

The indicia, within which term is included not only letters or figures such as 4 in Figure l, but also translucent windows 5, are formed on the surface of the sheet 2 adjacent to the outer or face sheet 1. Such indicia may be formed as interruptions in a background coating 6 produced either by a silk screen printing process, or by a photographic process, or by any other comparable process which will leave the indicia 4, 5 uncovered and will apply a dark background over the rest of the panel surface. If this background is sufficiently opaque to prevent penetration of light through it, such formation of the indicia on the front face of the sheet 2 may complete its processing.

Particularly where a silk screen process is used, however, frequently a perfectly opaque background coating cannot be produced by a single printing operation. Consequently, the background coating 6 on the front surface of the sheet 2 is supplemented by application of the background coating 7 to the back surface of the sheet 2. This background coating 7 may be applied in the same manner as the background coating 6 on the front face of the sheet 2, but in order to leave the indicia 4 and 5 on the front of the sheet undistorted and sharp, the uncoated portions 8 and 9 on the back surface of sheet 2, which correspond respectively to the lettering 4 and windows 5 on the front surface of the sheet, will be somewhat larger in areawhile following the same general outline. Thus the screen used for coating the back of the sheet 2 can be somewhat out of registry with the indicia on the front of the sheet without adversely atfecting the sharp outline of the indicia.

It would be possible to put two coats of background coating on the front face of the sheet 2 but it would be more diflicult to keep the outline of the indicia sharp. Where the second background coating 7 is applied to the back of sheet 2, however, it is desirable that this coating be covered with a further coating, such as 10, of white or other light colored paint or ink. Preferably light is supplied to the translucent indicia from a light transmitting sheet of material 3 bonded to the back surface of the intermediate sheet 2. It has been found that the black coating 7 on the back of the intermediate sheet tends to absorb light from the sheet 3 unless it is covered by such a reflective light colored coating 10.

In some instances it may be desirable to provide a clear Window 11 for transmission of light from the sheet 3. In that; case, as indicated in Figures 1 and 3, an aperture 11 of the desired size can simply be cut from the sheet 2. This aperture can then be filled with an insert piece of transparent or clear material of the same thickness as the sheet 2 The light transmission back sheet 3 preferably is formed of Lucite or Plexiglas or other clear acrylic plastic or similar sheet. The thickness of this sheet may be one-sixteenth of an inch to one-half inch, depending upon the over-all thickness of the panel desired and the intensity of the illumination. nated edgewise by a light received in a hole 12 in the composite panel in customary fashion.

When the indicia has been applied to the central sheet 2 in the manner described, the three sheets are placed under heat and pressure, and the sheets will be bonded together over their entire faces because of the thermoplastic characteristics of vinyl and acetate plastics. The desired apertures 12 for the light and mounting notches 13 may then be cut as desired in the finished panel, and the edges trimmed to the borderline 14 printed on the intermediate sheet 2. When the completed panel is illuminated from the front, the indicia will appear as the base color of the intermediate sheet. When the indicia is lighted by edgewise transmission of light through the sheet 3, however, the indicia will appear as. the color of the light, which may be white or some other color such as red or green.

In the alternative embodiment of the invention shown in Figures 4, 5 and 6, the outer or face sheet 1 is of the same type of material as the sheet 1 shown in Figures 1, 2 and 3, but in this instance it is shown to be somewhat thicker. Also, as in the embodiment previously described, the intermediate sheet 2 may be of white or other light colored translucent vinyl or acetate plastic sheet material, or it may be of neutral or even clear material of similar composition.

On the front surface of the intermediate sheet 2' the background coating 6 forming the indicia 4 and 5 is applied in the same way as described previously. Also, a window 11 may be provided in the sheet in the same manner. Moreover, the opaque background coating 7 may be applied to the back surface of the intermediate sheet 2' with larger void areas, 8 and 9 corresponding to the indicia on the opposite face of the sheet. Such additional background layer is optional, however, depending upon the completeness of the coverage of thecoating 6 on the face of the intermediate sheet.

Whether or not the coating 7 is applied to the back surface of the sheet 2', such entire surface, including the areas corresponding to indicia on the front surface of the sheet, will be covered by a coating 14 of light color.

In the example selected this coating has been lined to represent the color red, as distinguished from the lining for the color White of the coating 1'0 in Figure 3. It will be understood, however, that in this instance white can be used, if desired, and in the previous instance redor any other light color could be used instead of white.

The principal difference is when the sheets 1, 2" and 3 have been assembled to form thecompositepanel shown Such sheet may be illumiin Figure 5, if 2' is transparent the indicia will. appear to be the same color as the coating 14 even when the panel is illuminated from the front. This will also be true if the intermediate sheet 2' is of neutral color. However, if it is of reasonably heavy colored stock, such as white, the back coating 14 will not be appreciably visible when the panel is illuminated from the front.

The construction shown in. Figures 4, 5 and 6 enables the indicia to show as one color when the panel is illuminated from the front and a different color when the panel is illuminated by light transmitted through the sheet 3, while still providing a White or clear light in the window 11, or a light of color different from the indicia. When the indicia is illuminated by. light transmitted through the panel 3, all the indicia will appear to be like the color 14 even though the color of the stock from which the sheet 2 is made may be of a different light color. As a specific example, therefore, using white stock the indicia will appear white when the panel; is illuminated from the front, and. it will appear red when illuminated by light transmitted through the sheet 3 because of the red color of the over-all back coating 14.

The method of assembling the sheets 1', 2' and 3-is the same as that of assembling the sheets 1, 2 and 3', as described in connection with Figures 1, 2, and 3. Also, the completion of the panel shown in Figure 5 will be effected in a corresponding manner.

Coating of surfaces by silk screen or photographic procedures is sufficiently well known that no particular description of them in detail as utilized in the present panel manufacturing process should be required. It may be stated, however, that the indicia will be masked so as tov remain uncoated in the silk screen process. In the photographic process one or both sides of, the intermediate sheet is. coated, with photographic emulsion, which is exposed and developed so that the emulsion is removed in the areas forming the indicia to leave these spaces clear.

In some instances it may be desirable to have indicia which will glow in the dark even when the panel is not illuminated by light transmitted through the sheet 3. For this purpose the intermediate sheet 2 could be treated first by application of a clear vinyl plastic paint over its entire front face to which phosphorescent powder would adhere. The opaque. background is next applied by the silk screen process, for example, to the portions of the front, surface. other than the indicia. The phosphorescent powder will then be dusted on the. front surface. of the sheet 2 and will adhere, to the indicia portions. but not to the opaque background. When such an intermediate. sheetv is bonded to.v the front and back sheets the indicia will glow in the. dark.

While in the foregoing description the indicia has been described as being formed by the light transmitting portions of the panel, the processing of the indicia bearing sheet could be. altered so that the. indicia portion would be formed as an opaque coating on either side of the sheet and the rest. of the sheet would be of light transmitting. character, either transparent or translucent. As in the types 'of device described previously, the uncoated background could be, made of any light color desired, either by spraying on the back of the. sheet a particular color, or by utilizing. for the indicia bearing sheet stock of the color desired for. the background- The. procedure for applying the indicia. in this case would bev the same. except that the indicia and background portions. would simply have the opposite characteristics, respectively.

I claim as my invention:

A composite instrument panel comprising a back transparent light transmission sheet, an intermediate indiciabearing sheet, and a front transparent surface sheet, said three sheets being. intimately bonded in face-to-face relationship, said intermediate sheet being of translucent plastic material and having substantially opaque coatings on both faces thereof with registering openings, at leastone. of such openings constituting the indicia, and said inter-' mediate sheet having a light reflective coating on the opaque coating on the back face of said intermediate translucent plastic sheet.

References Cited in the file of this patent UNITED STATES PATENTS Scantlebury Apr. 2, 1929 

